Currently, there are a wide variety of portable, battery-powered consumer electronics products. Examples include cellular phones, digital cameras, laptop computers, and MP3 players. Typical products in this category are equipped with rechargeable batteries. However, in other cases such products are equipped to receive disposable batteries.
Most such products provide a DC power input, whether or not they come packaged with an external power adaptor. The DC power input is configured to receive an appropriate DC voltage to recharge the rechargeable battery, if present, and to power the device.
Power adaptors configured to supply DC power to such devices are well known. Typical examples include AC/DC adaptors configured to plug in to common household outlets, receive power at household AC, convert it to a DC voltage appropriate to the device, and supply the converted power to the DC device. Other examples include DC/DC converters adapted to receive power from automobile outlets (cigarette lighters) at 12 volts, convert it to a DC voltage appropriate to the device, and supply the converted power to the device.
Indeed, many modern devices that include rechargeable batteries come packaged with at least an AC/DC adaptor. Thus, when battery power runs low, and an outlet is available, the device can easily be powered and recharged simply by plugging the adaptor in and connecting it to the device.
Unfortunately, outlets, household or otherwise, and other power sources are not always available. A variety of portable power modules (PPM) have been marketed to solve this problem. A PPM is essentially a spare battery, designed to couple with a DC input of a DC powered device, such as a cellular phone, and discharge to provide an appropriate voltage.
The batteries within PPMs receive their power in a variety of ways. Some are configured to receive disposable batteries and convert their power to an appropriate voltage. Other PPMs include rechargeable batteries, and are configured to receive DC power through an input similar to those found in typical DC powered devices. Since a PPM for a given DC powered device is usually bought aftermarket, a typical arrangement is for that PPM to be configured to receive power from the AC/DC adaptor of that device, charging its battery.
Unfortunately, this design forces a user of a given DC powered device, say a cellular phone, needs to carry both its AC/DC adaptor and an appropriate PPM in order to ensure that extra power is available in every situation. Further, in order to recharge both the cellular phone and the PPM battery, the user must swap the output of the AC/DC adaptor between the two.